Question: Express your answer as a mixed number simplified to lowest terms. $18\dfrac{9}{10}-4\dfrac{12}{20} = {?}$
Answer: Separate the whole numbers from the fractional parts: $= {18} + {\dfrac{9}{10}} - {4} - {\dfrac{12}{20}}$ Bring the whole numbers together and the fractions together: $= {18} - {4} + {\dfrac{9}{10}} - {\dfrac{12}{20}}$ Subtract the whole numbers: $=14 + {\dfrac{9}{10}} - {\dfrac{12}{20}}$ Simplify each fraction: $= 14 + {\dfrac{9}{10}} - {\dfrac{3}{5}}$ Find a common denominator for the fractions: $= 14+\dfrac{9}{10}-\dfrac{6}{10}$ Subtract the fractions: $= 14+\dfrac{3}{10}$ Combine the whole and fractional parts into a mixed number: $= 14\dfrac{3}{10}$